The specialized immunologic system of the body's mucosal surfaces is characterized by the presence of the immunoglobulin, secretory IgA (sIgA). This system has been extensively studied in the gut, mammary gland, lung, and oral cavity, but not in the eye. The purpose of this project is to investigate the sIgA system of the eye. Our objectives are (1) to characterize the sites of potential sIgA synthesis in ocular tissues; (2) to determine the means of stimulating tear sIgA formation; (3) to determine the role of tear sIgA and IgA antibody in inhibiting bacterial adherence to ocular mucus; and (4) to explore whether nonantigenic homing of lymphoid cells to ocular sIgA synthesis areas occurs. The corresponding methods by which these objectives will be pursued are: (1) Examining lacrimal, accessory lacrimal, and conjunctival tissue by fluorescent antibody techniques for number and location of IgA-containing plasma cells and secretory component (SC) in epithelial cells in humans and rabbits. (2) Producing an animal model of bacterial conjunctivitis and measuring sIgA antibody in tears and IgG and IgA antibody in serum, and manipulating the model by vaccinating with killed bacteria via (a) conjunctiva, (b) lacrimal gland, (c) gut, (d) systemically, and then challenging ocularly with live bacteria. (3) An in vitro study with contact lenses covered with ocular mucus to which sIgA or IgG antibacterial antibody is added followed by the bacteria. (4) (a) Examining lacrimal and conjunctival tissues of stillborn humans for lymphoid cells. (b) Producing a model of one germ-free and one conventional eye in rabbits by performing a complete tarsorrhaphy at birth on one eye and then studying lymphoid cells in ocular tissues and tear sIgA antibody with and without immunization of the conventional eye.